Selective serotonin reuptake inhibitors (SSRIs) are the most commonly prescribed antidepressants. They can ease symptoms of moderate to severe depression, are relatively safe and generally cause fewer side effects than other types of antidepressants do.

How SSRIs work

SSRIs ease depression by affecting naturally occurring chemical messengers (neurotransmitters), which are used to communicate between brain cells. SSRIs block the reabsorption (reuptake) of the neurotransmitter serotonin in the brain. Changing the balance of serotonin seems to help brain cells send and receive chemical messages, which in turn boosts mood.

Most antidepressants work by changing the levels of one or more of these neurotransmitters. SSRIs are called selective because they seem to primarily affect serotonin, not other neurotransmitters.

SSRIs approved to treat depression

SSRIs approved by the Food and Drug Administration (FDA) to treat depression, with their generic names followed by brand names in parentheses, include:

Citalopram (Celexa)

Escitalopram (Lexapro)

Fluoxetine (Prozac)

Paroxetine (Paxil, Pexeva)

Sertraline (Zoloft)

Paxil CR is an SSRI that provides controlled release of the medication throughout the day or for a week at a time with a single dose.

SSRIs also may be used to treat conditions other than depression, such as anxiety disorders.

Side effects and cautions

All SSRIs work in a similar way and generally cause similar side effects. However, each SSRI has a different chemical makeup, so one may affect you a little differently than another. Most side effects may go away after the first few weeks of treatment, but talk to your doctor if any side effects are too troublesome for you.

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